exhaust performance dropped?

Question

i have recently changed the bullet for the exhaust system. usually i used 5 gear for driving even at low rpm, 1000rpm. now i must use 3 gear at low rpm. however the 1,2,3 gear peformance is better in torque and 4,5 gear is also better at high speed. what is wrong?

Answer 1

You changed the exhaust therefore the tuning is gone. Is very simple, when you buy a car with the stock system is set up for a wide range of conditions for street driving. Once you mess with it, you throw that to hell. This is a typical example of messing with the exhaust system in search of looks and sound.

The air is elastic so the gases down the tube runs in pulses. By making the tube bigger and wider the gases slows down, cools down and stall down the pipe. Therefore the incoming gases has to push it instead of purging itself out. Creates kind of a back slash or rubber band effect.

The best way to get the exhaust tuned is with a Dyno and test different lengths and width according to your driving preferences. Just watching an infomercial does not tells you that is the right setup for your car.

Answer 2

1,2,3 gears are supposed to be better in torque they multiply it and the higher gears are better for speed because they multiply less torque so less acceleration but more rpms so better speed

say u have 100 ft lbs of torque and your gear ratio is 4:1 at 4000 rpms your wheels will be getting 4 times the torque so 4 times 100 = 400 ft lbs of torque and your wheels will be getting 1/4 the rpm so it will be getting 1000rpm

now in fifth gear sayy the gear ratio .5:1 100 ft lbs of torque at 4000 rpm your tires will be getting 50 ft lbs of torque and 8000 rpm so you will be getting good speed but bad acceleration




some times if you change the exhaust system a little for higher or lower backpressure it changes the performance of the car and usually makes the mileage worse

Answer 3

what has happened is you have lost exhaust velocity most probably by going way too big a system for the airflow your engine is actually creating.
heat wrapping the header,down pipe, etc. all the way to expansion chamber will help.[if done right you should be able to touch the heat wrap even after repeated runs] but if chamber is too big you will just be making noise [of course if you are planning to turbocharge the car or replace the turbo that you have with a significantly larger one your system may be about right.
[note it is about this point that charged engines become aggrivating in traffic] while a nitrous system can get rid of boost lag there is the traffic to deal with an aftermarket management system and some time with a laptop can help out with this.

Answer 4

Even minor back pressure changes can make a performance change. With any air intake and exhaust modification you should also see a Dynometer tunner experenced with "Your Make model and Year car" to readjust the fuel maps and timing curve.